This invention relates to a chain driven bucket conveyor system for use with a mobile crop harvester, such as a grape harvester.
Wine grapes are mechanically harvested throughout the world by vigorously shaking the grapevine, breaking the individual berries loose from their capstems. When the capstems are pulled out of each berry, the berry starts to lose juice immediately. The more the fruit is tumbled in the conveyor system of the harvester, the more juice leaks out of each berry. After the fruit is removed during harvest, it is desirable to convey the fruit into the field trailers with as little tumbling and jostling as possible.
Generally speaking, there are two distinct types of conveyor systems used in the grape industry currently: (1) Continuous Belt Conveyor Systems and (2) Bucket Conveyor Systems.
The most universally used conveyor systems are the continuous belt type. These use a continuous belt approximately 18" wide, which is supported and driven by two 4" pulleys at each end of the belt. Each conveyor belt drops the fruit onto the next belt, conveying it out from under the vine, up to the top of the machine, out across the adjacent row into the trailer. A typical grape harvester will have eight belt conveyors to carry the fruit from each side of the vine into the trailer towed in the adjacent row.
The majority of the harvesters utilize a continuous belt conveyor because it is a simple, easily manufactured conveying system. It has, however, a number of disadvantages:
1. There are no effective ways to seal alongside the belt to avoid losing juice. PA1 2. It is difficult to scrape the juice which collects on the surface of the belt to transfer it to the next belt in the system. When there is a cleat required, as on a sloped conveyor belt, it is impossible to scrape it at all. PA1 3. Each transfer point between one conveyor belt and the next causes more juicing and mixing of the juice with the leaves in the conveyor belt. The more the leaves are coated with juice, the more difficult it is to remove them using the cleaning fans. PA1 1. Since the buckets act as belt cleats in the pick up section of the belt, the fruit has to be transferred off the belt into the buckets when the system moves into the vertical section of the conveyor. This transfer of the fruit cases the fruit to juice and mixes the juice with the leaves. These juice-coated leaves then become very difficult to remove during the cleaning phase. PA1 1. The chains stretch from use, leaving gaps between the buckets for fruit or juice to fall through onto the ground. PA1 2. The systems on the ends of the buckets used to hold the buckets erect and to tip them for dumping are quite fragile and complex. This results in may many malfunctions during operation. PA1 3. The attachment means for connecting the buckets to the chains, such as the U-shaped clips in the abovementioned patent, are easily snagged by the vines or the limbs of the plants being harvested. Such snagging can impose sufficiently high stresses on the buckets as to cause them to break during operation. In such case, the operator must either stop harvesting operations while the bucket is replaced, or continue harvesting with fruit dumping onto the ground through the gap at the broken bucket.
Many of these problems are alleviated by the bucket conveyor systems.
There are two types of bucket conveyor systems currently in use: (1) Those with buckets attached to a continuous belt, and (2) those with buckets attached to parallel drive chains.
The systems wherein the buckets are attached to a belt avoid most of the above disadvantages of the continuous belt conveyor system. However, they have disadvantages of their own:
The systems wherein the buckets are mounted on two parallel drive chains solves both the above problems associated with the continuous belt conveyor systems and those associated with the bucket-on-a-belt systems. An example of a chain-driven bucket conveyor system is that enclosed in U.S. Pat. No. 3,988,878, issued on Nov. 2, 1976. These systems have many advantages, the most important of which is that the fruit drops directly into the buckets as it is removed from the grapevine. During the entire conveying cycle (pick up, elevating and dumping) the fruit is protected inside the buckets without being tumbled or jostled.
However, all chain-driven bucket conveyor systems currently in use, including that disclosed in the aforementioned patent, have several disadvantages.